Multiple studies in recent years have identified highly tumorigenic populations of cells that drive tumor formation. These cancer stem cells (CSCs), or tumor-initiating cells (TICs), exhibit ...properties of normal stem cells and are associated with resistance to current therapies. As pancreatic adenocarcinoma is among the most resistant human cancers to chemo-radiation therapy, we sought to evaluate the presence of cell populations with tumor-initiating capacities in human pancreatic tumors. Understanding which pancreatic cancer cell populations possess tumor-initiating capabilities is critical to characterizing and understanding the biology of pancreatic CSCs towards therapeutic ends.
We have isolated populations of cells with high ALDH activity (ALDH(high)) and/or CD133 cell surface expression from human xenograft tumors established from multiple patient tumors with pancreatic adenocarcinoma (direct xenograft tumors) and from the pancreatic cancer cell line L3.6pl. Through fluorescent activated cell sorting (FACs)-mediated enrichment and depletion of selected pancreatic cancer cell populations, we sought to discriminate the relative tumorigenicity of cell populations that express the pancreatic CSC markers CD133 and aldehyde dehydrogenase (ALDH). ALDH(high) and ALDH(low) cell populations were further examined for co-expression of CD44 and/or CD24. We demonstrate that unlike cell populations demonstrating low ALDH activity, as few as 100 cells enriched for high ALDH activity were capable of tumor formation, irrespective of CD133 expression. In direct xenograft tumors, the proportions of total tumor cells expressing ALDH and/or CD133 in xenograft tumors were unchanged through a minimum of two passages. We further demonstrate that ALDH expression among patients with pancreatic adenocarcinoma is heterogeneous, but the expression is constant in serial generations of individual direct xenograft tumors established from bulk human pancreatic tumors in NOD/SCID mice.
We conclude that, in contrast to some previous studies, cell populations enriched for high ALDH activity alone are sufficient for efficient tumor-initiation with enhanced tumorigenic potential relative to CD133(+) and ALDH(low) cell populations in some direct xenograft tumors. Although cell populations enriched for CD133 expression may alone possess tumorigenic potential, they are significantly less tumorigenic than ALDH(high) cell populations. ALDH(high)/CD44(+)/CD24(+) or ALDH(low)/CD44(+)/CD24(+) phenotypes do not appear to significantly contribute to tumor formation at low numbers of inoculated tumor cells. ALDH expression broadly varies among patients with pancreatic adenocarcinoma and the apparent expression is recapitulated in serial generations of direct xenograft tumors in NOD/SCID. We have thus identified a distinct population of TICs that should lead to identification of novel targets for pancreatic cancer therapy.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
To review outcomes of locally advanced pancreatic cancer (LAPC) patients treated with dose-escalated intensity modulated radiation therapy (IMRT) with curative intent.
A total of 200 patients with ...LAPC were treated with induction chemotherapy followed by chemoradiation between 2006 and 2014. Of these, 47 (24%) having tumors >1 cm from the luminal organs were selected for dose-escalated IMRT (biologically effective dose BED >70 Gy) using a simultaneous integrated boost technique, inspiration breath hold, and computed tomographic image guidance. Fractionation was optimized for coverage of gross tumor and luminal organ sparing. A 2- to 5-mm margin around the gross tumor volume was treated using a simultaneous integrated boost with a microscopic dose. Overall survival (OS), recurrence-free survival (RFS), local-regional and distant RFS, and time to local-regional and distant recurrence, calculated from start of chemoradiation, were the outcomes of interest.
Median radiation dose was 50.4 Gy (BED = 59.47 Gy) with a concurrent capecitabine-based (86%) regimen. Patients who received BED >70 Gy had a superior OS (17.8 vs 15.0 months, P=.03), which was preserved throughout the follow-up period, with estimated OS rates at 2 years of 36% versus 19% and at 3 years of 31% versus 9% along with improved local-regional RFS (10.2 vs 6.2 months, P=.05) as compared with those receiving BED ≤70 Gy. Degree of gross tumor volume coverage did not seem to affect outcomes. No additional toxicity was observed in the high-dose group. Higher dose (BED) was the only predictor of improved OS on multivariate analysis.
Radiation dose escalation during consolidative chemoradiation therapy after induction chemotherapy for LAPC patients improves OS and local-regional RFS.
To assess the impact of postoperative complications on the receipt of adjuvant chemotherapy.
Randomized trials have demonstrated that adjuvant chemotherapy is associated with improved long-term ...survival. However, pancreatic surgery is associated with significant morbidity and the degree to which complications limit subsequent treatment options is unknown.
Patients from the American College of Surgeons National Surgical Quality Improvement Program and the National Cancer Data Base who underwent pancreatic resection for cancer were linked (2006-2009). The associations between complications and adjuvant chemotherapy use or treatment delay (≥ 70 days from surgery) were assessed using multivariable regression methods.
From 149 hospitals, 2047 patients underwent resection for stage I-III pancreatic adenocarcinoma of which 23.2% had at least 1 serious complication. Overall adjuvant chemotherapy receipt was 57.7%: 61.8% among patients not experiencing any complication and 43.6% among those who had a serious complication. Serious complications increased the likelihood of not receiving adjuvant therapy over twofold odds ratio (OR) = 2.20, 95% confidence interval (CI): 1.73-2.80. Specific complications associated with adjuvant chemotherapy omission were reintubation (OR = 7.79, 95% CI: 3.59-16.87), prolonged ventilation (OR = 5.92, 95% CI: 3.23-10.86), pneumonia (OR = 2.83, 95% CI: 1.63-4.90), sepsis/shock (OR = 2.76, 95% CI: 2.02-3.76), organ space/deep surgical site infection (OR = 2.19, 95% CI: 1.53-3.13), venous thromboembolism (OR = 1.92, 95% CI: 1.08-3.43), and urinary tract infection (OR = 1.61, 95% CI: 1.02-2.54). Serious complications also doubled the likelihood of delaying adjuvant treatment administration (OR = 2.08, 95% CI: 1.42-3.05). Sensitivity analysis in a younger, healthier patient cohort demonstrated similar associations.
Postoperative complications are common following pancreatic surgery and are associated with adjuvant chemotherapy omission and treatment delays.
Constitutive Kras and NF-κB activation is identified as signature alterations in pancreatic ductal adenocarcinoma (PDAC). However, how NF-κB is activated in PDAC is not yet understood. Here, we ...report that pancreas-targeted IKK2/β inactivation inhibited NF-κB activation and PDAC development in KrasG12D and KrasG12D;Ink4a/ArfF/F mice, demonstrating a mechanistic link between IKK2/β and KrasG12D in PDAC inception. Our findings reveal that KrasG12D-activated AP-1 induces IL-1α, which, in turn, activates NF-κB and its target genes IL-1α and p62, to initiate IL-1α/p62 feedforward loops for inducing and sustaining NF-κB activity. Furthermore, IL-1α overexpression correlates with Kras mutation, NF-κB activity, and poor survival in PDAC patients. Therefore, our findings demonstrate the mechanism by which IKK2/β/NF-κB is activated by KrasG12D through dual feedforward loops of IL-1α/p62.
► IKK2/β-activated NF-κB signaling pathway is required for KrasG12D-induced PDAC ► KrasG12D activated IKK2/β/NF-κB by inducing duel feedforward loops of IL-1α and p62 ► IL-1α correlates with Kras mutation, NF-κB activation, and poor survival in patients ► IL-1α is a therapeutic target to suppress KrasG12D-induced PDAC
PURPOSE Neuroendocrine tumors (NETs) are considered rare tumors and can produce a variety of hormones. In this study, we examined the epidemiology of and prognostic factors for NETs, because a ...thorough examination of neither had previously been performed. METHODS The Surveillance, Epidemiology, and End Results (SEER) Program registries were searched to identify NET cases from 1973 to 2004. Associated population data were used for incidence and prevalence analyses. Results We identified 35,618 patients with NETs. We observed a significant increase in the reported annual age-adjusted incidence of NETs from 1973 (1.09/100,000) to 2004 (5.25/100,000). Using the SEER 9 registry data, we estimated the 29-year limited-duration prevalence of NETs on January 1, 2004, to be 9,263. Also, the estimated 29-year limited-duration prevalence in the United States on that date was 103,312 cases (35/100,000). The most common primary tumor site varied by race, with the lung being the most common in white patients, and the rectum being the most common in Asian/Pacific Islander, American Indian/Alaskan Native, and African American patients. Additionally, survival duration varied by histologic grade. In multivariate analysis of patients with well-differentiated to moderately differentiated NETs, disease stage, primary tumor site, histologic grade, sex, race, age, and year of diagnosis were predictors of outcome (P < .001). CONCLUSION We observed increased reported incidence of NETs and increased survival durations over time, suggesting that NETs are more prevalent than previously reported. Clinicians need to be become familiar with the natural history and patterns of disease progression, which are characteristic of these tumors.
Tumor-associated macrophages (TAMs) represent the M2-like phenotype with potent immunosuppressive activity, and play a pro-tumor role in pancreatic ductal adenocarcinoma (PDAC) biology. In this ...study, we investigated the role of the insulin-like growth factor binding protein 2 (IGFBP2) as a determinant of TAM polarity. Clinical data revealed that the levels of IGFBP2 correlated with M2 TAMs accumulation and disease progression in human PDAC. In vivo mouse model experiments showed that IGFBP2 promoted an immunosuppressive microenvironment and tumor growth in a macrophage dependent manner. Bioinformatics analysis of PDAC transcriptomes revealed a significant association between IGFBP2 expression and M2 macrophage polarization and signal transducer and activator of transcription 3 (STAT3) activation. Mechanistic investigations demonstrated that IGFBP2 augmented the expression and secretion of IL-10 through STAT3 activation in PDAC cells, which induced TAM polarization toward an M2 phenotype. IGFBP2-polarized M2 macrophages significantly increased Tregs infiltration and impaired antitumor T-cell immunity in a mouse model. Thus, our investigations have illuminated the IGFBP2 signaling pathway that contributes to the macrophage-based immunosuppressive microenvironment in PDAC, suggesting that blocking the IGFBP2 axis constitutes a potential treatment strategy to reset TAM polarization toward an antitumor state in PDAC.
•High IGFBP2 correlates with M2 TAM accumulation and disease progression in human PDAC.•IGFBP2 augments IL-10 by STAT3 activation in PDAC cells, inducing M2 TAM polarization.•IGFBP2-polarized M2 TAMs increase Treg infiltration and impair antitumor T-cell immunity.•Blocking IGFBP2 offers a potential strategy to reset TAM polarization toward an antitumor state in PDAC.
Understanding the mechanism of radioresistance could help develop strategies to improve therapeutic response of patients with PDAC. The
gene is frequently mutated in pancreatic cancer. In this study, ...we investigated the role of
deficiency in pancreatic cancer cells' response to radiotherapy.
We downregulated SMAD4 expression with
siRNA or
shRNA and overexpressed SMAD4 in
mutant pancreatic cancer cells followed by clonogenic survival assay to evaluate their effects on cell radioresistance. To study the mechanism of radioresistance, the effects of
loss on reactive oxygen species (ROS) and autophagy were determined by flow cytometry and immunoblot analysis, respectively. Furthermore, we measured radioresistance by clonogenic survival assay after treatment with autophagy inhibitor (Chloroquine) and ROS inhibitor (N-acetyl-l-cysteine) in
-depleted pancreatic cancer cells. Finally, the effects of
on radioresistance were also confirmed in an orthotopic tumor model derived from
-depleted Panc-1 cells.
-depleted pancreatic cancer cells were more resistant to radiotherapy based on clonogenic survival assay. Overexpression of wild-type SMAD4 in
-mutant cells rescued their radiosensitivity. Radioresistance mediated by
depletion was associated with persistently higher levels of ROS and radiation-induced autophagy. Finally,
depletion induced
radioresistance in Panc-1-derived orthotopic tumor model (
= 0.038). More interestingly, we observed that the protein level of SMAD4 is inversely correlated with autophagy in orthotopic tumor tissue samples.
Our results demonstrate that defective
is responsible for radioresistance in pancreatic cancer through induction of ROS and increased level of radiation-induced autophagy.
.
Background & Aims Obesity is a risk factor for pancreatic ductal adenocarcinoma (PDAC), but it is not clear how obesity contributes to pancreatic carcinogenesis. The oncogenic form of KRAS is ...expressed during early stages of PDAC development and is detected in almost all of these tumors. However, there is evidence that mutant KRAS requires an additional stimulus to activate its full oncogenic activity and that this stimulus involves the inflammatory response. We investigated whether the inflammation induced by a high-fat diet, and the accompanying up-regulation of cyclooxygenase-2 (COX2), increases Kras activity during pancreatic carcinogenesis in mice. Methods We studied mice with acinar cell−specific expression of KrasG12D (LSL-Kras/Ela-CreERT mice) alone or crossed with COX2 conditional knockout mice (COXKO/LSL-Kras/Ela-CreERT). We also studied LSL-Kras/PDX1-Cre mice. All mice were fed isocaloric diets with different amounts of fat, and a COX2 inhibitor was administered to some LSL-Kras/Ela-CreERT mice. Pancreata were collected from mice and analyzed for Kras activity, levels of phosphorylated extracellular-regulated kinase, inflammation, fibrosis, pancreatic intraepithelial neoplasia (PanIN), and PDACs. Results Pancreatic tissues from LSL-Kras/Ela-CreERT mice fed high-fat diets (HFDs) had increased Kras activity, fibrotic stroma, and numbers of PanINs and PDACs than LSL-Kras/Ela-CreERT mice fed control diets; the mice fed the HFDs also had shorter survival times than mice fed control diets. Administration of a COX2 inhibitor to LSL-Kras/Ela-CreERT mice prevented these effects of HFDs. We also observed a significant reduction in survival times of mice fed HFDs. COXKO/LSL-Kras/Ela-CreERT mice fed HFDs had no evidence for increased numbers of PanIN lesions, inflammation, or fibrosis, as opposed to the increases observed in LSL-Kras/Ela-CreERT mice fed HFDs. Conclusions In mice, an HFD can activate oncogenic Kras via COX2, leading to pancreatic inflammation and fibrosis and development of PanINs and PDAC. This mechanism might be involved in the association between risk for PDAC and HFDs.
OBJECTIVE:To investigate the legitimacy of 90-day mortality as a measure of hepatopancreatobiliary quality.
BACKGROUND:The 90-day mortality rate has been increasingly but not universally reported ...after hepatopancreatobiliary surgery. The legitimacy of this definition as a measure of surgical quality has not been evaluated.
METHODS:We retrospectively reviewed the causes of all deaths that occurred within 365 postoperative days in patients undergoing hepatectomy (n = 2811) and/or pancreatectomy (n = 1092) from January 1997 to December 2012. The rates of surgery-related, disease-related, and overall mortality within 30 days, within 30 days or during the index hospitalization, within 90 days, and within 180 days after surgery were calculated.
RESULTS:Seventy-nine (3%) surgery-related deaths and 92 (3%) disease-related deaths occurred within 365 days after hepatectomy. Twenty (2%) surgery-related deaths and 112 (10%) disease-related deaths occurred within 365 days after pancreatectomy. The overall mortality rates at 99 and 118 days optimally reflected surgery-related mortality after hepatobiliary and pancreatic operations, respectively. The 90-day overall mortality rate was a less sensitive but equivalently specific measure of surgery-related death.
CONCLUSIONS AND RELEVANCE:The 99- and 118-day definitions of postoperative mortality optimally reflected surgery-related mortality after hepatobiliary and pancreatic operations, respectively. However, among commonly reported metrics, the 90-day overall mortality rate represents a legitimate measure of surgical quality.
Background: Portal lymphadenectomy (PLND) is the current standard for oncologic resection of biliary tract cancers (BTCs). However, published data show it is performed infrequently and often yields ...less than the recommended 6 lymph nodes. We sought to identify yield and outcomes using a Clockwise Anterior-to-Posterior technique with Double Isolation of critical structures (CAP-DI) for PLND. Methods: Consecutive patients undergoing complete PLND for BTCs using CAP-DI technique were identified (2015−2021). Lymph node (LN) yield and predictors of LN count were examined. Secondary outcomes included intraoperative and postoperative outcomes, which were compared to patients having hepatectomy without PLND. Results: In total, 534 patients were included; 71 with complete PLND (36 gallbladder cancers, 24 intrahepatic cholangiocarcinomas, 11 perihilar cholangiocarcinomas) and 463 in the control group. The median PLND yield was 5 (IQR 3−8; range 0−17) and 46% had at least 6 nodes retrieved. Older age was associated with lower likelihood of ≥6 node PLND yield (p = 0.032), which remained significant in bivariate analyses with other covariates (p < 0.05). After adjustment for operative factors, performance of complete PLND was independently associated with longer operative time (+46.4 min, p = 0.001), but no differences were observed in intraoperative or postoperative outcomes compared to the control group (p > 0.05). Conclusions: Yield following PLND frequently falls below the recommended minimum threshold of 6 nodes despite a standardized stepwise approach to complete clearance. Older age may be weakly associated with lower PLND yield. While all efforts should be made for complete node retrieval, failure to obtain 6 nodes may be an unrealistic metric of surgical quality.
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